Electronic trip device with short delay function

Claim 1

A short delay function electronic trip device designed to produce a tripping signal when an input signal, representative of a current flowing in at least one conductor to be protected, is greater than a preset threshold value over a preset time delay period, said trip device comprising: comparison means for comparing the input signal and the threshold value and for producing an output signal when the input signal is greater than the threshold value, and time delay means connected to the output of the comparison means, wherein the time delay means comprises a counter and an up-down counter each comprising a clock input coupled to receive clock signals of preset frequencies from a clock circuit, a zero reset input of the counter being connected to the output of the comparison means, and the output of the counter being connected to an up-down counting input of the up-down counter in such a way as to trigger its count-down when the content of the counter reaches a first preset value, wherein the up-down counter generates a tripping signal when its content reaches a second preset value.